1. Field of the Invention
The present invention relates to a photoelectric conversion circuit for performing photoelectric conversion, a data transmission apparatus for performing data transmission, and a test apparatus for testing an electronic device. More particularly, the present invention relates to a data transmission apparatus based on optical transmission.
2. Related Art
In data communication, the trend towards higher speed and larger capacity is recently significant. In short distance transmission such as indoor transmission, parallel optical transmission is now the prevailing method, when performing large-sized data communication at high speed. A data transmission apparatus for performing data transmission by the parallel optical transmission includes a plurality of channels, each of which consists of a laser diode, an optical fiber, and a photodiode, and uses the channels to perform data transmission.
In accordance with the trend towards high speed data communication, however, there occurs a problem of skew between the channels. For example, due to the skew, the speed of data communication is restricted. In the conventional data transmission apparatus, a complicated framing circuit and a coding circuit are provided to the transmitter side, whereas an encoding circuit being provided to the receiver side, to reduce the skew, but there occurs a problem that the power consumption is high, and the response decreases.
Also, even in the test apparatus to test the electronic device, in accordance with the trend towards a high speed device under test and a small-sized test apparatus, it is desirable that a data transmission apparatus used for data communication have high speed, small size, high density, and low power consumption characteristics.